This invention relates to a printing drum.
As described in Kellett, U.S. Ser. No. 08/645,747, titled MATERIALS USEFUL IN LITHOGRAPHIC PRINTING PLATES, filed May 14, 1996, incorporated by reference herein, a continuous jet printer can be used to prepare a printing plates for offset printing. Typically in offset printing, four separate aluminum plates are used to produce a single color image. Each of the four plates is engraved with a partial image used to print one of four colors: cyan, magenta, yellow and black. Because four plates are used to produce a single image, the partial images must be precisely aligned on the drum and on the printing press.